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<title>Overview of Ajax - The Java EE 6 Tutorial</title>
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      <td width="400px"><p class="toc level1"><a href="docinfo.html">Document Information</a></p>
<p class="toc level1 tocsp"><a href="gexaf.html">Preface</a></p>
<p class="toc level1 tocsp"><a href="gfirp.html">Part&nbsp;I&nbsp;Introduction</a></p>
<p class="toc level2"><a href="bnaaw.html">1.&nbsp;&nbsp;Overview</a></p>
<p class="toc level2"><a href="gfiud.html">2.&nbsp;&nbsp;Using the Tutorial Examples</a></p>
<p class="toc level1 tocsp"><a href="bnadp.html">Part&nbsp;II&nbsp;The Web Tier</a></p>
<p class="toc level2"><a href="bnadr.html">3.&nbsp;&nbsp;Getting Started with Web Applications</a></p>
<p class="toc level2"><a href="bnaph.html">4.&nbsp;&nbsp;JavaServer Faces Technology</a></p>
<p class="toc level2"><a href="giepx.html">5.&nbsp;&nbsp;Introduction to Facelets</a></p>
<p class="toc level2"><a href="gjddd.html">6.&nbsp;&nbsp;Expression Language</a></p>
<p class="toc level2"><a href="bnaqz.html">7.&nbsp;&nbsp;Using JavaServer Faces Technology in Web Pages</a></p>
<p class="toc level2"><a href="gjcut.html">8.&nbsp;&nbsp;Using Converters, Listeners, and Validators</a></p>
<p class="toc level2"><a href="bnatx.html">9.&nbsp;&nbsp;Developing with JavaServer Faces Technology</a></p>
<p class="toc level2"><a href="gkmaa.html">10.&nbsp;&nbsp;JavaServer Faces Technology Advanced Concepts</a></p>
<p class="toc level2"><a href="bnawo.html">11.&nbsp;&nbsp;Configuring JavaServer Faces Applications</a></p>
<p class="toc level2"><a href="gkiow.html">12.&nbsp;&nbsp;Using Ajax with JavaServer Faces Technology</a></p>
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<p class="toc level3"><a href="">Overview of Ajax</a></p>
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<p class="toc level3"><a href="gkinl.html">Using Ajax Functionality with JavaServer Faces Technology</a></p>
<p class="toc level3"><a href="gkabr.html">Using Ajax with Facelets</a></p>
<p class="toc level4"><a href="gkabr.html#gkafn">Using the <tt>f:ajax</tt> Tag</a></p>
<p class="toc level3 tocsp"><a href="gkace.html">Sending an Ajax Request</a></p>
<p class="toc level4"><a href="gkace.html#gkhvt">Using the <tt>event</tt> Attribute</a></p>
<p class="toc level4"><a href="gkace.html#gkhuz">Using the <tt>execute</tt> Attribute</a></p>
<p class="toc level4"><a href="gkace.html#gkhwm">Using the <tt>immediate</tt> Attribute</a></p>
<p class="toc level4"><a href="gkace.html#gkhzs">Using the <tt>listener</tt> Attribute</a></p>
<p class="toc level3 tocsp"><a href="gkddf.html">Monitoring Events on the Client</a></p>
<p class="toc level3"><a href="gkdcb.html">Handling Errors</a></p>
<p class="toc level3"><a href="gkdbr.html">Receiving an Ajax Response</a></p>
<p class="toc level3"><a href="gkuar.html">Ajax Request Lifecycle</a></p>
<p class="toc level3"><a href="gkhyh.html">Grouping of Components</a></p>
<p class="toc level3"><a href="gkaam.html">Loading JavaScript as a Resource</a></p>
<p class="toc level4"><a href="gkaam.html#gkafi">Using JavaScript API in a Facelets Application</a></p>
<p class="toc level4"><a href="gkaam.html#gkipx">Using the <tt>@ResourceDependency</tt> Annotation in a Bean Class</a></p>
<p class="toc level3 tocsp"><a href="gkokb.html">The <tt>ajaxguessnumber</tt> Example Application</a></p>
<p class="toc level4"><a href="gkokb.html#gkoij">The <tt>ajaxguessnumber</tt> Source Files</a></p>
<p class="toc level5"><a href="gkokb.html#gkofw">The <tt>ajaxgreeting.xhtml</tt> Facelets Page</a></p>
<p class="toc level5"><a href="gkokb.html#gkofx">The <tt>ui.js</tt> JavaScript File</a></p>
<p class="toc level5"><a href="gkokb.html#gkohn">The <tt>UserNumberBean</tt> Managed Bean</a></p>
<p class="toc level4 tocsp"><a href="gkokb.html#gkoke">Building, Packaging, Deploying, and Running the <tt>ajaxguessnumber</tt> Example</a></p>
<p class="toc level5"><a href="gkokb.html#glhvu">To Build, Package, and Deploy the <tt>ajaxguessnumber</tt> Example Using NetBeans IDE</a></p>
<p class="toc level5"><a href="gkokb.html#glhvq">To Build, Package, and Deploy the <tt>ajaxguessnumber</tt> Example Using Ant</a></p>
<p class="toc level5"><a href="gkokb.html#glhwe">To Run the <tt>ajaxguessnumber</tt> Example</a></p>
<p class="toc level3 tocsp"><a href="gksdk.html">Further Information about Ajax in JavaServer Faces</a></p>
<p class="toc level2 tocsp"><a href="gkhxa.html">13.&nbsp;&nbsp;Advanced Composite Components</a></p>
<p class="toc level2"><a href="bnavg.html">14.&nbsp;&nbsp;Creating Custom UI Components</a></p>
<p class="toc level2"><a href="bnafd.html">15.&nbsp;&nbsp;Java Servlet Technology</a></p>
<p class="toc level2"><a href="bnaxu.html">16.&nbsp;&nbsp;Internationalizing and Localizing Web Applications</a></p>
<p class="toc level1 tocsp"><a href="bnayk.html">Part&nbsp;III&nbsp;Web Services</a></p>
<p class="toc level2"><a href="gijti.html">17.&nbsp;&nbsp;Introduction to Web Services</a></p>
<p class="toc level2"><a href="bnayl.html">18.&nbsp;&nbsp;Building Web Services with JAX-WS</a></p>
<p class="toc level2"><a href="giepu.html">19.&nbsp;&nbsp;Building RESTful Web Services with JAX-RS</a></p>
<p class="toc level2"><a href="gjjxe.html">20.&nbsp;&nbsp;Advanced JAX-RS Features</a></p>
<p class="toc level2"><a href="gkojl.html">21.&nbsp;&nbsp;Running the Advanced JAX-RS Example Application</a></p>
<p class="toc level1 tocsp"><a href="bnblr.html">Part&nbsp;IV&nbsp;Enterprise Beans</a></p>
<p class="toc level2"><a href="gijsz.html">22.&nbsp;&nbsp;Enterprise Beans</a></p>
<p class="toc level2"><a href="gijre.html">23.&nbsp;&nbsp;Getting Started with Enterprise Beans</a></p>
<p class="toc level2"><a href="gijrb.html">24.&nbsp;&nbsp;Running the Enterprise Bean Examples</a></p>
<p class="toc level2"><a href="bnbpk.html">25.&nbsp;&nbsp;A Message-Driven Bean Example</a></p>
<p class="toc level2"><a href="gkcqz.html">26.&nbsp;&nbsp;Using the Embedded Enterprise Bean Container</a></p>
<p class="toc level2"><a href="gkidz.html">27.&nbsp;&nbsp;Using Asynchronous Method Invocation in Session Beans</a></p>
<p class="toc level1 tocsp"><a href="gjbnr.html">Part&nbsp;V&nbsp;Contexts and Dependency Injection for the Java EE Platform</a></p>
<p class="toc level2"><a href="giwhb.html">28.&nbsp;&nbsp;Introduction to Contexts and Dependency Injection for the Java EE Platform</a></p>
<p class="toc level2"><a href="gjbls.html">29.&nbsp;&nbsp;Running the Basic Contexts and Dependency Injection Examples</a></p>
<p class="toc level2"><a href="gjehi.html">30.&nbsp;&nbsp;Contexts and Dependency Injection for the Java EE Platform: Advanced Topics</a></p>
<p class="toc level2"><a href="gkhre.html">31.&nbsp;&nbsp;Running the Advanced Contexts and Dependency Injection Examples</a></p>
<p class="toc level1 tocsp"><a href="bnbpy.html">Part&nbsp;VI&nbsp;Persistence</a></p>
<p class="toc level2"><a href="bnbpz.html">32.&nbsp;&nbsp;Introduction to the Java Persistence API</a></p>
<p class="toc level2"><a href="gijst.html">33.&nbsp;&nbsp;Running the Persistence Examples</a></p>
<p class="toc level2"><a href="bnbtg.html">34.&nbsp;&nbsp;The Java Persistence Query Language</a></p>
<p class="toc level2"><a href="gjitv.html">35.&nbsp;&nbsp;Using the Criteria API to Create Queries</a></p>
<p class="toc level2"><a href="gkjiq.html">36.&nbsp;&nbsp;Creating and Using String-Based Criteria Queries</a></p>
<p class="toc level2"><a href="gkjjf.html">37.&nbsp;&nbsp;Controlling Concurrent Access to Entity Data with Locking</a></p>
<p class="toc level2"><a href="gkjia.html">38.&nbsp;&nbsp;Improving the Performance of Java Persistence API Applications By Setting a Second-Level Cache</a></p>
<p class="toc level1 tocsp"><a href="gijrp.html">Part&nbsp;VII&nbsp;Security</a></p>
<p class="toc level2"><a href="bnbwj.html">39.&nbsp;&nbsp;Introduction to Security in the Java EE Platform</a></p>
<p class="toc level2"><a href="bncas.html">40.&nbsp;&nbsp;Getting Started Securing Web Applications</a></p>
<p class="toc level2"><a href="bnbyk.html">41.&nbsp;&nbsp;Getting Started Securing Enterprise Applications</a></p>
<p class="toc level1 tocsp"><a href="gijue.html">Part&nbsp;VIII&nbsp;Java EE Supporting Technologies</a></p>
<p class="toc level2"><a href="gijto.html">42.&nbsp;&nbsp;Introduction to Java EE Supporting Technologies</a></p>
<p class="toc level2"><a href="bncih.html">43.&nbsp;&nbsp;Transactions</a></p>
<p class="toc level2"><a href="bncjh.html">44.&nbsp;&nbsp;Resource Connections</a></p>
<p class="toc level2"><a href="bncdq.html">45.&nbsp;&nbsp;Java Message Service Concepts</a></p>
<p class="toc level2"><a href="bncgv.html">46.&nbsp;&nbsp;Java Message Service Examples</a></p>
<p class="toc level2"><a href="gkahp.html">47.&nbsp;&nbsp;Advanced Bean Validation Concepts and Examples</a></p>
<p class="toc level2"><a href="gkeed.html">48.&nbsp;&nbsp;Using Java EE Interceptors</a></p>
<p class="toc level1 tocsp"><a href="gkgjw.html">Part&nbsp;IX&nbsp;Case Studies</a></p>
<p class="toc level2"><a href="gkaee.html">49.&nbsp;&nbsp;Duke's Tutoring Case Study Example</a></p>
<p class="toc level1 tocsp"><a href="idx-1.html">Index</a></p>
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<a name="gkigr"></a><h2>Overview of Ajax</h2>
<a name="indexterm-823"></a><p>Ajax refers to JavaScript and XML, technologies that are widely used for creating
dynamic and asynchronous web content. While Ajax is not limited to JavaScript and
XML technologies, more often than not they are used together by web applications.
The focus of this tutorial is on using JavaScript based Ajax functionality in JavaServer
Faces web applications.</p>

<p>JavaScript is a dynamic scripting language for web applications. It is an object-oriented
language that allows users to add enhanced functionality to user interfaces and allows
web pages to interact with clients asynchronously. JavaScript mainly runs on the client
side (such as a browser) and thereby reduces server access by clients.</p>

<p>When a JavaScript function sends an asynchronous request from the client to the
server, the server sends back a response which is used to update
the page's Document Object Model (DOM). This response is often in the format
of a XML document. The term Ajax refers to this interaction between the
client and server.</p>

<p>The server response need not be in XML only but can also
be in other formats such as <a href="http://www.json.org/">JSON</a>. This tutorial does not focus on the
response formats.</p>

<p>Ajax enables asynchronous and partial updating of web applications. Such functionality allows for
highly responsive web pages that are rendered in near real time. Ajax based
web applications can access server and process information as well as retrieve data
without interfering with the display and rendering of the current web page on
a client (such as a browser).</p>

<p>Some of the advantages of using Ajax are as follows:</p>


<ul><li><p>Form data validation in real time, eliminating the need to submit the form for verification</p>

</li>
<li><p>Enhanced functionality for web pages, such as username and password prompts</p>

</li>
<li><p>Partial update of the web content, avoiding complete page reloads</p>

</li></ul>

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